Mr. Summers apparently assumes that spending on transit confers little or no spill-over benefits on non-riders. Unfortunately, a very recent independent study by the National Bureau of Economic Research demonstrates the falsity of Mr. Summers' assumption. The study reports large benefits in reduced peak-hour traffic congestion for private auto drivers when transit services are available.

An analogy for Mr. Summers' argument comes to mind: spending our tax dollars on prisons is wasteful because the great majority of us never use prisons. Q.E.D.?